S
TARTING
UP
AND
OPERATING
C
HAPTER
7
THP 94/42 R 4 XXT
THP 125/42 R 4 XXT
THP 140 H/42 R 4 XXT
GB-07.2005
7-26
•
The pump speed is too high, reduce the pump speed
•
The distribution boom is badly positioned, move the distribution boom to a better position
Example of a badly positioned distribution boom: Boom fully extended, element 4 vertical
7.6.3
Instructions for pumping (depending on the material to be pumped)
NOTE:
墌
Only ever use pumpable concrete!
墌
If you are unsure, contact the concrete manufacturer.
•
If pumping concrete that is hard to pump, the agitator shaft should be visible at all times!
Difficult concrete (extremely stiff, low-sand mixtures, light-weight concrete etc.) will pump better when the
hopper is filled only to the lower edge of the agitator shaft. This procedure means that air will be drawn by the
concrete pump into the conveying cylinder and the concrete will be conveyed in air plug mode. Caution,
blockages may occur!
•
The pressure should be relieved in the conveying pipework by brief reversal of the pump (2-3 strokes) during
pauses in conveying. Frequently pump back and forwards. Never allow the conveying pipework to stand
under pressure.
•
If the concrete is very fluid, with a high proportion of large gravel, and tends to bleed from the conveying
pipework, always pump out into the hopper during pauses in pumping.
•
During longer pauses pump the concrete back into the hopper, mix it and pump it through again.
•
During longer pauses in pumping, switch off the drive engine, so that its vibrations do not cause the concrete
to separate out. At intervals of 10-15 minutes, pump the concrete back and forth.
•
Never force concrete that has separated out, or concrete that is lumpy because it is beginning to set, through
the conveying pipework.
•
Especially with concrete that has a low capacity for retaining water (tendency to bleed) avoid pauses when
working at high throughputs, and when restarting conveying be sure to let the pump run long enough for the
transfer tubes on both sides to be filled. Only then switch over to forwards conveying again.
•
Air inclusions in the conveying pipework can be hazardous, since compressed air can emerge violently at the
discharge hose, causing concrete to spray out explosively.
Air inclusions occur particular when pumping through by sucking in air when the hopper is insufficiently filled
with concrete and when the conveying pipework has been extended.
•
The characteristics of the concrete must not be changed in any way.
